Related papers: Heavy element nucleosynthesis in rotating proto-ma…
We present a new astrophysical site of the big bang nucleosynthesis (BBN) that are very peculiar compared with the standard BBN. Some models of the baryogenesis suggest that very high baryon density regions were formed in the early…
The origin of nucleosynthesis products of rapid neutron capture reactions (the r-process) is a longstanding astrophysical problem. Recent analyses of elemental abundances for extremely metal-poor stars shed light on the elemental abundances…
The rapid neutron-capture process or r-process is thought to produce the majority of the heavy elements (Z > 30) in extremely metal-poor stars. The same process is also responsible for a significant fraction of the heavy elements in the…
We calculate the structure and neutron content of neutrino-heated MHD winds driven from the surface of newly-formed magnetars (``proto-magnetars'') and from the midplane of hyper-accreting disks, two of the possible central engines for…
We reanalyze $r$-process nucleosynthesis in the neutron-rich ejecta from a prompt supernova explosion of a low-mass (11 M$_\odot$) progenitor. A pompt explosion is not yet ruled out as a possibility for low-mass supernova progenitors.…
The astrophysical origin of the lanthanides is an open question in nuclear astrophysics. Besides the widely studied $s$, $i$, and $r$ processes in moderately-to-strongly neutron-rich environments, an intriguing alternative site for…
If the r-process occurs deep within a Type II supernova, probably the most popular of the proposed sites, abundances of r-process elements may be altered by the intense neutrino flux. We point out that the effects would be especially…
Neutron emission probabilities and half-lives of 37 beta-delayed neutron emitters from 75Ni to 92Br were measured at the RIKEN Nishina Center in Japan, including 11 one-neutron and 13 two-neutron emission probabilities and 6 half-lives…
We investigate the nucleosynthesis process in high-entropy ($s/k_{\rm B}\gtrsim100$) and very fast-expanding ($\tau_{\rm exp}\sim10^{-3}\ {\rm s}$) materials. In such a material with the electron fraction near 0.5, an interesting…
We suggest that part of the infalling material during the core-collapse of a massive star goes into orbit around the compact core to form a hot, dense, centrifugally-supported accretion disk whose evolution is strongly influenced by…
Fast spinning magnetars are discussed as strong sources of high energy neutrinos. Pulsars may be born with a short rotation period of milliseconds with the magnetic field amplified through dynamo processes up to $\sim 10^{15}-10^{16} \rm…
The neutrino-driven wind from a nascent neutron star at the center of a supernova expands into the earlier ejecta of the explosion. Upon collision with this slower matter the wind material is decelerated in a wind termination shock. By…
Magnetars are a sizable subclass of the neutron star census. Their very high magnetic field strengths are thought to be a consequence of rapid (millisecond) rotation at birth in a successful core-collapse supernova. In their first tens of…
The wind driven by the intense neutrino emission from a protoneutron star (PNS) is an important site for producing nuclei heavier than the Fe group. Because of certain features in the neutrino angular distributions, the so-called fast…
Solving Newtonian steady-state wind equations with accurate weak interaction rates and magnetic fields (MFs) of young neutron stars considered, we study the dynamics and nucleosynthesis of neutrino-driven winds (NDWs) from proto neutron…
In preparation for a set of hydrodynamical simulations of core-collapse supernovae and protoneutron star winds, we investigate the rates of production and thermalization of $\nu_\mu$ and $\nu_\tau$ neutrinos in dense nuclear matter.…
We discuss the possibility whether superheavy elements can be produced in Nature by the astrophysical rapid neutron capture process. To this end we have performed fully dynamical network r-process calculations assuming an environment with…
We have made detailed calculations of the composition of magnetically driven jets ejected from collapsars, or rapidly rotating massive stars, based on long-term magnetohydrodynamic simulations of their core collapse with various…
Nuclear masses play a fundamental role in understanding how the heaviest elements in the Universe are created in the $r$-process. We predict $r$-process nucleosynthesis yields using neutron capture and photodissociation rates that are based…
We present a state-of-the-art scenario for newly born magnetars as strong sources of Gravitational Waves (GWs)in the early days after formation. We address several aspects of the astrophysics of rapidly rotating, ultramagnetized neutron…